|Isotope||Atomic mass (Da)||Isotopic abundance (amount fraction)|
In 1969, the Commission recommended Ar(Ir) = 190.22(3) based on a closer analysis of earlier mass-spectrometric determinations. In 1993, the Commission changed the recommended value for the standard atomic weight of iridium to Ar(Ir) = 192.217(3) based on recent high-precision measurements using both positive and negative thermal ionization mass spectrometry. The new value represents a significant improvement in the precision of the atomic weight and is in agreement with the previous measurements.
© IUPAC 2003